It doesn't even have to be competitors their suppliers would love to know the total amount of widgets that they'll be buying. That way they know if they're the single supplier

It tells them exactly how much they have to invest in hardware buildout to stay competitive with Google in terms of raw compute.

This is right up there with being able to predict a competitor's total manufacturing capacity for the next year because you have hard numbers on their raw material purchase.

The ability to improve their data centers, of course. Google is the company that launched data centers with commodity components.